A research team led by Professor Eilhann E. Kwon of the Department of Earth Resources and Environmental Engineering at Hanyang University has secured a technology for recycling the waste of polylactic acid (PLA), a biodegradable plastic. This technology is expected to contribute to the development of alternative fuel production technology and resource recycling of PLA waste by producing gas that can be used as fuel as well as effectively converting PLA waste into PLA monomer in a state before waste through a pyrolysis process.

With the perception that PLA is biodegradable, it is used in various industries, from 3D printer filaments to straws. However, there have been challenges in the biodegradation of PLA waste, as it requires specific conditions of temperature and humidity. This has led to considering biodegradable plastics, including PLA, as contributors to microplastic pollution, alongside petroleum-based plastics. In addition, as PLA is mainly produced from food resources like corn, it is relatively more expensive to manufacture than petroleum-based plastics. This has raised ethical concerns about using food resources for chemical product manufacturing.

Professor Kwon’s team proposed a pyrolysis process using carbon dioxide to overcome these problems. In this process, carbon dioxide facilitates the thermal degradation of PLA, selectively increasing the recovery of its monomers. Moreover, this approach generates gases that can be used as fuel, addressing the issues associated with PLA disposal and creating a more sustainable pathway for its utilization.

Professor Kwon explained the significance of this research by stating, “Through the technology of resource utilization and monomer production from PLA waste, we can contribute to the expected increase in the treatment and production cost reduction of PLA waste.”

As a follow-up, Professor Kwon’s research team focuses on developing technology for utilizing pyrolytic oil produced through PLA thermal degradation. This effort aims not only to produce PLA monomers but also to develop techniques for generating alternative fuels and high-value compounds.

This research was conducted with support from the Ministry of Science and ICT, the Ministry of Education, and the National Research Foundation of Korea. The findings, under the paper titled “Virtuous utilization of carbon dioxide in pyrolysis of polylactic acid in the field of chemical engineering,” were published on June 15 in the prestigious international academic journal Chemical Engineering Journal. 

■ Author information: Professor Eilhann E. Kwon (corresponding author, Hanyang University), PhD student Seong-Heon Cho (first author, Hanyang University), PhD student You-Kwan Kim (coauthor, Hanyang University), PhD student Sang-Yoon Lee (coauthor, Hanyang University)